Sciurus carolinensis 


Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Mammalia Rodentia Sciuridae

Scientific Name: Sciurus carolinensis
Species Authority: Gmelin, 1788
Common Name(s):
English Eastern Gray Squirrel, Gray Squirrel, Grey Squirrel

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2008
Date Assessed: 2008-06-30
Assessor(s): Linzey, A.V., Koprowski, J. & NatureServe (Hammerson, G.)
Reviewer(s): Amori, G. (Small Nonvolant Mammal Red List Authority) & Chanson, J. (Global Mammal Assessment Team)
Listed as Least Concern because of its wide distribution, large population, occurrence in a number of protected areas, no major threats, and it is tolerant to habitat disturbance and its population is increasing.
Previously published Red List assessments:
1996 Lower Risk/least concern (LR/lc)

Geographic Range [top]

Range Description:This species is found in the eastern United States and adjacent southern Canada; southern Quebec to Manitoba, south to eastern Texas and Florida. Its range has been extended through introductions into Quebec, Ontario, New Brunswick, Manitoba, Saskatchewan, British Columbia, Nova Scotia, California, Oregon, Washington, and Montana (Teaford 1986, Koprowski 1994). It is also introduced in the British Isles, Italy, South Africa, and Australia (extirpated by 1973), but these introduced ranges are not included in the map here (see Koprowski 1994).
Countries occurrence:
Canada; United States
Italy; South Africa; United Kingdom
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:This species is widespread and abundant. Reported densities vary from <3/ha in continuous woodlands to >21/ha in urban parks. Population and range are increasing (J Koprowski pers. comm.).
Current Population Trend:Increasing
Additional data:
Population severely fragmented:No

Habitat and Ecology [top]

Habitat and Ecology:It is found in large blocks of hardwood or mixed forests, as well as in urban and suburban areas. Prefers mature deciduous and mixed forests with abundant supplies of mast (e.g., acorns, hickory nuts). A diversity of nut trees is needed to support high densities. Also uses city parks and floodplains. Seldom far from permanent open water. In southern Alabama, narrow bands of hardwoods along ephemeral streams were an important component of the habitat in even-aged pine and mixed pine-hardwood stands. Rests in tree cavity or leaf nest; leaf nests apparently are made primarily by dispersing juveniles 18-19 weeks old. Nests in tree cavities or in leaf nests, usually 25 feet or more above the ground. Most winter-spring litters are born in tree cavities, most spring-summer litters in leaf nests (Teaford 1986). Cavities suitable for nesting are dry, 15-25 cm in diametre, 40-50 cm deep, with an entrance hole about eight cm in diameter (Teaford 1986). Females may move young from tree cavity nest to leaf nest, possibly to escape fleas.

In Illinois, most breeding occurs in December-February and May-June; slightly later in more northern latitudes (see Koprowski 1994). One or two litters per year. First litter is produced mostly in February-March, sometimes as early as January in some areas; second litter, July or August. Gestation lasts 44 days. Litter size most often is 2-3. Young are tended by female. Weaning is completed at about 10-12 weeks (in spring and/or late summer-early fall). Most breed as yearlings, sometimes sooner (as early as five months) or later. Reproductive output, including the percentage of adults that produce young and the number of litters per year, is positively correlated with mast abundance. Maximum reproductive longevity is about a decade.

Home range averages 0.5-10 ha, with older males tending to have the largest ranges (Teaford 1986); usually home range is less than five hectares (see Koprowski 1994). Not territorial, home range overlap is extensive; social system is characterized by a linear dominance hierarchy. Disperses up to a few kilometres from natal area upon approaching sexual maturity. Large-scale one-way emigrations have been observed, generally coinciding with high population density and mast crop failure.

Taken by many predators, but predation does not appear to limit populations (Teaford 1986). Mean annual mortality reported for adults is 42-57% (Koprowski 1994). Diet consists of seeds, fruits, nuts, fungi, occasional insects and small vertebrates (e.g., bird eggs). Scatterhoarder; buries nuts and acorn in fall for later consumption (winter-spring). Active during the day, particularly in the morning and late afternoon, though unimodal activity may occur in winter. May be inactive for a day or two during extremely cold, snowy weather.

Threats [top]

Major Threat(s): There are no major threats to this species.

Conservation Actions [top]

Conservation Actions: The species occurs in a number of protected areas throughout its range.

Classifications [top]

1. Forest -> 1.4. Forest - Temperate
suitability: Suitable  
14. Artificial/Terrestrial -> 14.3. Artificial/Terrestrial - Plantations
suitability: Suitable  
14. Artificial/Terrestrial -> 14.4. Artificial/Terrestrial - Rural Gardens
suitability: Suitable  

In-Place Research, Monitoring and Planning
In-Place Land/Water Protection and Management
  Conservation sites identified:Yes, over entire range
In-Place Species Management
In-Place Education

Bibliography [top]

Koprowski, J. L. 1994. Sciurus carolinensis. Mammalian Species 480: 1-9.

Teaford, J. W. 1986. Eastern gray squirrel (Sciurus carolinensis). Section 4.7.1, US Army Corps of Engineers Wildlife Resources Management Manual. Technical Report.

Wilson, D.E. and Ruff, S. 1999. The Smithsonian Book of North American Mammals. Smithsonian Institution Press, Washington, DC, USA.

Citation: Linzey, A.V., Koprowski, J. & NatureServe (Hammerson, G.). 2008. Sciurus carolinensis. In: The IUCN Red List of Threatened Species 2008: e.T42462A10699433. . Downloaded on 24 May 2016.
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